Suppression of Hepatitis B Virus Replication by MicroRNA-199a-3p and MicroRNA-210

Accumulating evidence suggests that microRNAs (miRNAs) control the replication of both RNA and DNA viruses. In order to determine whether host-encoded miRNAs affect hepatitis B virus (HBV) replication, antisense oligonucleotides (ASOs) of 328 identified human miRNAs were transfected into HepG2 2.2.15 cells, respectively. ELISA and MTS assay were used to measure the expression level of HBV S protein (HBsAg), HBV e antigen (HBeAg) and cell proliferation. Compared to experimental controls, miR-199a-3p and miR-210 efficiently reduced HBsAg expression without affecting HepG2 2.2.15 cell proliferation. Quantification of HBV DNA by real-time PCR showed that both miRNAs suppressed viral replication. Bioinformatics analysis indicated a putative binding site for miR-199a-3p in the HBsAg coding region and a putative binding site for miR-210 in the HBV pre-S1 region. The direct effect of miRNAs on the target region in HBV transcripts was validated by a fluorescent reporter assay, and the suppression of HBs gene expression by both miRNAs was measured by real-time PCR and Western blot. These results suggest that up-regulation of miR-199a-3p and miR-210 in HepG2 2.2.15 cells compared to HepG2 cells may play a role in regulating HBV replication and maintenance of a suitable level of virion production in persistent infection by targeting crucial HBV genes.